Average Woman Weighs 171 Pounds

The average man weighs 198 pounds. These figures come from the the federal government's National Health and Nutrition Examination Survey, which measures the heights and weights of a nationally representative sample of the population. Here's the trend in the age-adjusted weight of men and women since the turn of the century...

Average weight of men aged 20-plus (in pounds)
2015–2016: 198
2009–2010: 196
1999–2000: 189

Average weight of women aged 20-plus (in pounds)
2015–2016: 171
2009–2010: 166
1999–2000: 164

While weights have increased over the years, heights have remained the same. The 2015–16 survey found the average man to be a bit over 5 feet 9 inches tall. The average woman is almost 5 feet 4 inches in height. These heights have barely budged since 2000.

With heights unchanged and weight increasing, body mass index is rising. The average man has a body mass index of 29.1, up from 27.8 in 1999–00. The average woman has a body mass index of 29.6, up from 28.2 in 1999–00. A BMI of 25 or higher is considered overweight, so the average American is overweight. A BMI of 30 or higher is considered obese, so the average American is very close to being obese.

Source: National Center for Health Statistics, National Health and Nutrition Examination Survey, Mean Body Weight, Height, Waist Circumference, and Body Mass Index among Adults: United States, 1999–2000 through 2015–16